The present invention relates to a heat shield for shielding of hot areas, e.g. of an internal combustion engine, and a method to produce such heat shield.
Such heat shields for instance in engines of vehicles, in particular in the area of the exhaust line, serve for the protection of temperature-sensitive parts or assemblies from non-permissible overheating, which parts or assemblies are located close to hot parts. This way, the heat shields also improve sound protection. It is important to make sure that the transmission of sound from the hot part to the heat shield is minimized, especially at the fastening points of the heat shield at the part. If the heat shield is fastened at the hot part or at one of the hot parts, one also has to ascertain that the heat transmission is low.
Usually, such heat shields are three-dimensionally shaped structural parts, which comprise at least one metal sheet layer. The three-dimensional shape of the at least one metal sheet layer usually results from the shape of the parts to be shielded against each other and their distance with respect to one another.
Usually, a heat shield comprises one or several metal sheet layers, which define the contour of the heat shield. It can also be advantageous if additional insulation layers, e.g. compressed particle-based layers, such as mica- or graphite-based layers, or temperature-stable fiber-based material, such as glass fiber-based material, e.g. glass fiber fleece and/or mineral fiber-based material, such as mineral-fiber fleece or temperature-stable paper are arranged between the individual metal sheet layers or adjacent to one or several of the metal sheet layers.
Fastening of the heat shield to the part is usually realized using a point-wise connection. To this end, the metal sheet layer or all of the metal sheet layers can comprise a passage opening, which takes up the fastening element. Screws, bolts, studs with transverse pins or rivets can be used here as fastening elements.
At these fastening points, vibrations from the part, in case of fastening at the hot part also heat, can be transmitted via the fastening element from the part to the heat shield.
Therefore, the fastening element needs to be isolated and/or dampened relative to the adjacent metal sheet layer(s) through which it passes.